Saturday, May 30, 2015

5/30: This is a test...

The infantry (our beach/paleoclimate team of Mike, Julie, Julia, and Sam) set out for their first day. Hopefully their early trip recon. will yield some interesting insight, ideas, and inspiration for their projects as they take form this week.

Michael Carroll (Akvaplan-niva), Al Wanamaker (Iowa State), and I (Thornton Academy) are out today to retrieve moorings from the small boat and test our GoPro underwater filming capabilities. I will post more once we get back and I can work up the files but here is a quick clip of our test in super low-resolution, taken from the base camp dock. 

The video posted above was taken from a GoPro Hero 3 attached with a roll bar mount onto a ~10 ft. pvc pole. The pole is ideal for filming from the boat (our dock!) at low speed and minimal depth because it gives us a static connection underwater which will not spin or dance about in the water simply due to our grip holding it steady. Now, how do we take this out in the field?
Post-test computer and GoPro staging station
Goal: We want to get underwater footage of the seafloor habitat at our clambed locations. Quite a bit of meaningful data can be gleaned from such video, or still shots taken out of it. Having worked for years on marine ecosystems through the overtop ice surface or from a boat, it can be extremely valuable to have a normally off limits, first hand visual account of being immersed in the environment you're investigating. 

Thorleif and Michael survey our options. Use a lure mount? Is the rubber fin enough stabilization?
Problem: How do we engineer a device for underwater footage of the seabed in ocean waters deeper than our pvc pole will reach? It must be stable, not rotate, and be guided along a drift-transect from the boat at the surface.
This room sums up the tools and materials at our disposal. Thorleif is very generous to allow us to explore solutions. 
Solution: TA engineers, how do you think this will work? Open for comments from Mr. Slack/Lukas/Hall...

We ended up using a heavy rock anchor, the reel-end of a former fishing rod, zip-ties (god love 'em), and a wooden sail constructed from a 1x4 plank and a 1/8" plywood vane. Our hope is that during a near dead-drift, the camera will be positioned at the ideal location above the bottom (w/o anchor dragging) and the 'sail' will stabilize the camera mount. Remember that even though the whole rig will rotate as a rigid body if it moves but that means a larger arc length swept out by the end of the sail will translate to a very small disturbance to the camera view opposite. Any flotation of the wood will be counteracted by the braced mount to the line and the weight of the heavy anchor. We think this should be enough stabilization to provide adequate shooting conditions. 

Michael and Al model the new video-rig.
I predict Hollywood will be making a long distance call shortly...
With the seas/wind dying down a bit, it is almost time to hit the ocean. We'll let you know how it turns out. 

No comments:

Post a Comment